The present invention relates to a method of surface machining for a substrate of an electrophotographic photoreceptor, and more particularly, to a method of surface machining of a substrate made of aluminum of an electrophotographic photoreceptor.
In an electrophotographic copying machine, a digital copier, a laser printer and others, an electrophotographic photoreceptor wherein a light-sensitive layer is provided on a substrate of a rotary drum-shaped electrophotographic photoreceptor (hereinafter referred to simply as "substrate") is commonly used. As a material of the substrate forming such electrophotographic photoreceptor, materials of an aluminum type are preferably used from the viewpoint of low cost, lightness and easy machining. A rotary drum-shaped substrate made of the aluminum type material is generally made by turning the surface of a cylindrical material for finishing, and cutting liquid is usually used for the cutting work of turning. The cutting liquid is used for the purpose of cooling, lubricating and cleaning, and for that purpose, petroleum, polybutene, kerosene and white kerosene are used.
Actual technologies related to a method of surface machining for a substrate of an electrophotographic photoreceptor which have been suggested are as follows.
(1) A technology wherein a substrate of an electrophotographic photoreceptor is machined by the use of cutting oil containing 1.0% by weight or less of an oiliness improver and/or extreme-pressure additive (Japanese Patent Publication Open to Public Inspection No. 307463/1988 (hereinafter referred to as Japanese Patent O.P.I. Publication).
(2) A technology wherein the surface of a substrate of an electrophotographic photoreceptor is made of an aluminum alloy containing magnesium, silicon, copper and titanium each within a specific range of values is machined by a cutting tool having a rounded shape at its cutting portion (Japanese Patent O.P.I. Publication No. 86151/1989).
(3) A technology wherein an alloy containing silicon and iron each within a specific range of values is used for a substrate of an electrophotographic photoreceptor (Japanese Patent O.P.I. Publication No. 86152/1989).
(4) A technology wherein the surface of a substrate of an electrophotographic photoreceptor made of an aluminum alloy containing magnesium, silicon, and copper each within a specific range of values is machined by a cutting tool having a rounded shape at its cutting portion (Japanese Patent O.P.I. Publication No. 86153/1989).
(5) A technology wherein an alloy containing silicon, magnesium and iron each within a specific range of values is used for a substrate of an electrophotographic photoreceptor (Japanese Patent O.P.I. Publication No. 86154/1989).
(6) A technology wherein an alloy containing magnesium, silicon, copper and titanium each within a specific range of values is used for a substrate of an electrophotographic photoreceptor (Japanese Patent O.P.I. Publication No. 86155/1989).
(7) A technology wherein an alloy containing silicon, iron, and magnesium, each within a specific range of values and containing other metals within a specified range of values is used for a substrate of an electrophotographic photoreceptor (Japanese Patent O.P.I. Publication No. 123245/1989)
(8) A technology employing a surface machining apparatus which is composed of a lathe unit, a high-pressure liquid jetting unit and a conveyance unit for a substrate of an electrophotographic photoreceptor, and is capable of turning and high-pressure jetting successively and automatically (Japanese Patent O.P.I. Publication No. 152642/1987)
(9) A technology employing a specific cutting liquid supplying nozzle apparatus having a spindle head on which a spindle equipped with a rotary tool having oil holes and a rotary tool having no oil holes is supported rotatably (Japanese Patent O.P.I. Publication No. 152642/1987).
(10) A technology wherein high pressure water is jetted onto the surface of a substrate of an electrophotographic photoreceptor from a nozzle connected to a source of high-pressure water supply while the surface of the substrate is scanned by the nozzle, thereby the surface of the substrate is matted to the predetermined surface roughness (Japanese Patent O.P.I. Publication No. 264764/1988).
In the past, however, the supply of cutting liquid was unstable, resulting in insufficient cooling of a cutting tool which shortened its life, because an operator used his experience and head for supplying cutting liquid. In addition to that, a temperature of cutting liquid was unstable, and change of ambient temperature and heat generated from a surface machining apparatus adversely affected dimensions of the surface-machined substrate, which has been a problem.